Absorption is a process where the components of a gaseous stream are separated through the use of a liquid solvent. The process may be simply physical or be followed by a chemical reaction. In industry, one of the most important absorption processes is the removal of carbon dioxide (CO2), by using an aqueous solution of monoethanolamine (MEA), from flue gases exhausted by fossil-fuel-fired power plants, the pharmaceutical industry, the petroleum industry, etc. The projects developed by large companies usually are surrounded by secrecy and the companies avoid dissemination of their technological solutions. In addition, there is almost nothing published in Brazil about this subject. In this work, we present a simple model that simulates the absorption of CO2 by a MEA based aqueous solution. The model involves the equations for the conservation of mass, momentum, and energy, and may predict the general behavior of the absorption process. Results for the simulation of the absorption of CO2 in a countercurrent liquid film contactor were compared with available experimental data, presenting good agreement.